1. Field of the Invention
Aspects of the present invention relate to a scanning apparatus, and more particularly, to a scanning apparatus that corrects an image distortion generated in scanning a book.
2. Description of the Related Art
In general, a scanning apparatus scans an image of a document to form an image data having a predetermined resolution. As shown in FIGS. 1A and 1B, a conventional scanning apparatus 10 includes a stage glass 20 on which a document is loaded, and a scanning head 30 under the stage glass 20 that scans an image of the document. The scanning head 30 includes a light source module 31 that emits a light to scan the document, and a photoelectric converting element 33 that senses the light reflected from the document and converts such light into an electric image signal.
In the conventional scanning apparatus 10, if the scanning head 30 moves to scan a book, as shown in FIG. 1B, an area of the book around a binding A fails to directly contact the stage glass 20 and is distanced from the stage glass 20 by a predetermined distance d1. However, a page area B directly contacts the stage glass 20. Accordingly, differences of focal distances (or lengths) between the light source module 31 and the surface of the book (i.e., differences between the distances between the light source module 31 and the area near the binding A and the page area B) result in distortions respectively generated with respect to the different areas of the surface of the book by the photoelectric converting element 33 (i.e., I1≠I2). As shown in FIG. 1C, due to the differences of the focal distances as the scanning head 30 moves, a spatial distortion area is generated in a scanned image near the binding A, resulting in spatial distortion as well as a darker image.